1. Field of the Invention
The present invention relates to a printed circuit board with electronic devices mounted thereon and, more particularly, to a printed circuit board equipped with a cooler having a sealed case wherein a liquid coolant is passed over the printed circuit board having mounted thereon LSIs or similar semiconductor devices of large calorific power.
2. Background of the Related Art
Because of the recent increase in the LSI integration density as well as the recent speeding up of LSI operations, calorific power that individual high-density LSIs generate keeps on increasing. Such being the case, there is a demand for the development of a more efficient cooling unit for a high-density-LSI-mounted, printed circuit board. The LSI-mounted printed circuit board has a required number of LSIs mounted on one or both sides of the board. To cool the LSIS, it is customary in the prior art to cool the entire structure of the LSI-mounted printed circuit board by forced air cooling or liquid cooling of the type that soaks the printed circuit board in a liquid coolant.
The forced air cooling does not sufficiently achieve the intended purpose of cooling LSIs of large calorific power. The liquid cooling involves the immersion of the whole printed circuit board structure in the coolant, and hence it has a defect that the cooler therefor is inevitably bulky. In addition, since the liquid cooling of the printed circuit board substantially relies on convection of the coolant, it is impossible to produce a satisfactory effect of cooling the printed circuit board when electronic devices of large calorific power are mounted thereon.